1. Technical Field
This application is the US national phase of international application PCT/GB2005/001064 filed 21 Mar. 2005 which designated the U.S. and claims benefit of GB 0407369.8, dated 31 Mar. 2004, the entire content of which is hereby incorporated by reference.
The present invention relates to a trust token or identity confirmation device and more particularly, but not exclusively, to such a token or device for use in electronic certification.
2. Related Art
Any transaction requires an element of trust between the participants. The notion of trust can be formalised along the following lines. Suppose we have a situation in which one party (B) has offered some commitment to another party (A), possibly in return for some reciprocal commitment. Party A cannot be certain that B will complete its commitment. If party A accepts the offer from B, it will subsequently act on the assumption that B will complete its commitment—for example by providing a service to B in the expectation that B will pay for it or, conversely, by paying B in advance for a service B is expected to provide. Should B fail to do so, then A may suffer some loss.
As a rational agent, A will only accept B's offer if it perceives the risks to be outweighed by the probable benefits, where ‘risk’ takes into account the probability of B failing to deliver and the cost to A of this eventuality. If A accepts, then it can be said to “trust” B in the context of this transaction. The degree of perceived risk involved is a measure of the amount of trust A is placing in B.
When conducting transactions electronically, for example over an open distributed system such as the “Internet”, there are a number of particular problems that arise in establishing trust. In particular it is quite possible that the parties will have had little or no prior contact or knowledge of reputation or brand. For example, one party may have found the other using an on-line directory of some sort. It is also relatively difficult to confirm the identity of the other party. For example one of the parties may be disguising itself as a more reputable party.
One method of establishing trust between parties is disclosed in our co-pending United Kingdom patent application no 0405623.0. In order to provide trust certification a third party trusted by one of the parties can be used to certify the transaction and provided that that third party is also trusted by the other party mutual trust can be established.
The third party to a transaction may be thought of as an identity provider which certifies the identity of parties to a transaction. This identity provider may be implemented as a centralised server or server cluster providing identities on behalf of all of its subscribers—that is the owners of the identities being certified.
In published United States Patent Application No. US2003/0140223—Desideri, there is disclosed an identity authentication system in which a smart card or other storage device includes data defining a biometric characteristic certified by an authority such as a passport office and includes a digital signature or private key which in combination with a public key may be used to identify an individual present at a point of sale terminal.
Such a system requires the user to be present in the same place as the transaction takes place. This is not entirely a suitable arrangement for e-commerce or for user certification of an interactive computer session.
In one example of interactive computer sessions, for example where single sign on access to multiple servers is required a central server to which the user is logged on and which “trusts” the identity of the user issues tokens which certify trust for the session with other servers.